Cold sores on the skin of the mouth occur when herpes simplex viruses that are dormant in neural ganglia become active and travel to the skin of the mouth. What is the mechanism by which these viruses travel from the ganglia (located within the head) to the skin of the mouth?

Anterograde transport

Explanation:

Cells utilize tracks of microtubules in order to transport cellular cargo in either of two directions: anterograde and retrograde. Retrograde transport refers to motion from the periphery of the cell to the center, and is accomplished by the motor protein dynein. Anterograde transport refers to motion from the center of the cell to the periphery, and is accomplished by the motor protein kinesin. Speaking of herpes the virus is in the ganglia which can be considered as the inner or center location and the skin of the mouth would be considered the periphery.

In neurons, anterograde transport is especially important as it supplies vital proteins and vesicles to pre-synaptic junctions. In addition, anterograde transport is used in molecular biology to visualize entire neurons by injecting a marker into the cell body and allowing the cell to move it to the periphery. This technique, known as anterograde tracing, has been used to visualize the axonal projections of specific neurons.

Anterograde transport supplies distal axons with newly synthesized proteins and lipids, including synaptic components required to maintain presynaptic activity. Retrograde transport is required to maintain homeostasis by removing aging proteins and organelles from the distal axon for degradation and recycling of components.